Eight viruses have been identified which are members of the family Herpesviridae (reviewed in Roizman, B. 1996. Herpesviridae, p. 2221-2230. In B. N. Fields, D. M. Knipe, and P. M. Howley (ed.), Fields Virology, 3rd ed. Lippincott-Raven Publishers, Philadelphia, Pa.). Each member of this family is characterized by an enveloped virus containing proteinaceous tegument and nucleocapsid, the latter of which houses the viruses"" relatively large double-stranded DNA genome (i.e. approximately 80-250 kilobases). Members of the human alphaherpesvirus subfamily are neurotropic and include herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), and varicella-zoster virus (VZV). The human betaherpesviruses are cytomegalovirus (HCMV), human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7). The gammaherpesviruses are lymphotropic and include Epstein-Barr virus (EBV) and Kaposi""s herpesvirus (HHV-8). Each of these herpesviruses is causally-related to human disease, including herpes labialis and herpes genitalis (HSV-1 and HSV-2 [Whitley, R. J. 1996. Herpes Simplex Viruses, p. 2297-2342. In B. N. Fields, D. M. Knipe, and P. M. Howley (ed.), Fields Virology, 3rd ed. Lippincott-Raven Publishers, Philadelphia, Pa.]); chicken pox and shingles (VZV [Arvin, A. 1996. Varicella-Zoster Virus, p. 2547-2585. In B. N. Fields, D. M. Knipe, and P. M. Howley (ed.), Fields Virology, 3rd ed. Lippincott-Raven Publishers, Philadelphia, Pa.]); infectious mononucleosis (EBV [Rickinson, A. B. and Kieff, E. 1996. Epstein-Barr Virus, p. 2397-2446. In B. N. Fields, D. M. Knipe, and P. M. Howley (ed.), Fields Virology, 3rd ed. Lippincott-Raven Publishers, Philadelphia, Pa.]); pneumonia and retinitis (HCMV [(Bitt, W. J., and Alford, C. A. 1996. Cytomegalovirus, p. 2493-2523. In B. N. Fields, D. M. Knipe, and P. M. Howley (ed.), Fields Virology, 3rd ed. Lippincott-Raven Publishers, Philadelphia, Pa.]); exanthem subitum (HHV-6 [(Pellet, P. E, and Black, J. B. 1996. Human Herpesvirus 6, p. 2587-2608. In B. N. Fields, D. M. Knipe, and P. M. Howley (ed.), Fields Virology, 3rd ed. Lippincott-Raven Publishers, Philadelphia, Pa.] and HHV-7 [Frenkel, N., and Roffman, E. 1996. Human Herpesvirus 7, p. 2609-2622. In B. N. Fields, D. M. Knipe, and P. M. Howley (ed.), Fields Virology, 3rd ed. Lippincott-Raven Publishers, Philadelphia, Pa.]); and Kaposi""s sarcoma (HHV-8 [Neipel, F., Albrecht, J. C., and Fleckenstein, B. 1997. Cell-homologous genes in the Kaposi""s sarcoma-associated rhadinovirus human herpesvirus 8: determinants of its pathogenicity? J. Virol. 71:4187-92, 1997]). HCMV is considered in more detail below. Following the primary infection, herpesviruses establish latency within the infected individual and remain there for the remainder of his/her life. Periodic reactivation of latent virus is clinically relevant. In the case of HSV, reactivated virus can be transmitted to infants during birth, causing either skin or eye infection, central nervous system infection, or disseminated infection (i.e. multiple organs or systems). Shingles is the clinical manifestation of VZV reactivation. Treatment of HSV and VZV is generally with antiviral drugs such as acyclovir (Glaxo Wellcome), ganciclovir (Roche) and foscarnet (Asta) which target viral encoded DNA polymerase.
HCMV is a ubiquitous opportunistic pathogen infecting 50-90% of the adult population (Britt, W. J., and Alford, C. A. 1996. Cytomegalovirus, p. 2493-2523. In B. N. Fields, D. M. Knipe, and P. M. Howley (ed.), Fields Virology, 3rd ed. Lippincott-Raven Publishers, Philadelphia, Pa.). Primary infection with HCMV is usually asymptomatic, although heterophile negative mononucleosis has been observed. The virus is horizontally transmitted by sexual contact, breast milk, and saliva. Intrauterine transmission of HCMV from the pregnant mother to the fetus occurs and is often the cause of serious clinical consequences. HCMV remains in a latent state within the infected person for the remainder of his/her life. Cell-mediated immunity plays a central role in controlling reactivation from latency. Impaired cellular immunity leads to reactivation of latent HCMV in seropositive persons.
HCMV disease is associated with deficient or immature cellular immunity. There are 3 major categories of persons with HCMV disease (reviewed by Britt and Alford, 1996). (1) In immunocompromised (AIDS) patients, HCMV is one of the two most common pathogens causing clinical disease (the other is Pneumocystis). The most common manifestation of HCMV in AIDS is retinitis, although infection of other organs including the adrenal glands, lungs, GI tract, and central nervous system are also reported frequently. 90% of AIDs patients have active HCMV infection; 25-40% (xcx9c85,000 patients in the United States) have life- or sight-threatening HCMV disease. HCMV is the cause of death in 10% of persons with AIDs. (2) Due to immune system suppression to reduce the risk of graft rejection, HCMV reactivation or reinfection is common amongst kidney, liver, heart, and allogeneic bone marrow transplant patients. Pneumonia is the most common HCMV disease in these patients, occurring in up to 70% of these transplant patients. (3) Congenital infection due to HCMV occurs in 1% of all births, about 40K per year. Up to 25% of these infants are symptomatic for HCMV disease between ages 0-3 years. HCMV disease is progressive, causing mental retardation and neurological abnormalities, in children. Recent studies suggest that treatment with anti-HCMV drugs may reduce morbidity in these children.
Several antiviral drugs are currently being marketed (Bron, D., R. Snoeck, and L. Lagneaux. 1996. New insights into the pathogenesis and treatment of cytomegalovirus. Exp. Opin. Invest. Drugs 5:337-344: Crumpacker, C. 1996. Ganciclovir. New Eng. J. Med. 335:721-729; Sachs, S., and F. Alrabiah. 1996. Novel herpes treatments: a review. Exp. Opin. Invest. Drugs 5:169-183). These include: ganciclovir (Roche), a nucleoside analog with hemopoietic cell toxicity; foscarnet (Astra), a pyrophosphate analog with nephrotoxicity; and cidofovir, Gilead), a nucleoside phosphonate with acute nephrotoxicity. Each of these drugs target the viral-encoded DNA polymerase, are typically administered intravenously due to their low bioavailability, and, as noted above, are the source of significant toxicity. Ganciclovir-resistant mutants which arise clinically are often cross-resistant with cidofovir. Hence, there is a need for safer (i.e. less toxic), orally bioavailable anti-viral drugs which are directed against novel viral targets.
Phenyl thioureas are disclosed for use in a variety of pharmaceutical applications. Armistead, et al., WO 97/40028, teaches phenyl ureas and thioureas as inhibitors of the inosine monophosphate dehydrogenase (IMPDH) enzyme which is taught to play a role in viral replication diseases such herpes.
Widdowson, et al., WO 96/25157, teaches phenyl urea and thiourea compounds of the below formula for treating diseases mediated by the chemokine, interleukin-8. 
Morin, Jr., et al., U.S. Pat. No. 5,593,993 teaches certain phenyl thiourea compounds for treatment of AIDs and the inhibition of the replication of HIV and related viruses.
Therefore, it is an object of this invention to provide compounds, and pharmaceutically acceptable salts thereof, to inhibit and/or treat diseases associated with herpes viruses including human cytomegalovirus, herpes simplex viruses, Epstein-Barr virus, varicella-zoster virus, human herpesviruses-6 and -7, and Kaposi herpesvirus.
In accordance with the present invention are provided compounds having the formula: 
wherein
R1-R5 are independently selected from hydrogen, alkyl of 1 to 6 carbon atoms, alkenyl of 2 to 6 carbon atoms, alkynyl of 2 to 6 carbon atoms, perhaloalkyl of 1 to 6 carbon atoms, cycloalkyl of 3 to 10 carbon atoms, heterocycloalkyl of 3 to 10 carbon members, aryl, heteroaryl, halogen, xe2x80x94CN, xe2x80x94NO2, xe2x80x94CO2R6, xe2x80x94COR6, xe2x80x94OR6, xe2x80x94SR6, xe2x80x94SOR6, xe2x80x94SO2R6, xe2x80x94CONR7R8, xe2x80x94NR6N(R7R8), xe2x80x94N(R7R8) or Wxe2x80x94Yxe2x80x94(CH2)nxe2x80x94Z provided that at least one of R1-R5 is not hydrogen; or R2 and R3 or R3 and R4, taken together form a 3 to 7 membered heterocycloalkyl or 3 to 7 membered heteroaryl:
R6 and R7 are independently hydrogen, alkyl of 1 to 6 carbon atoms, perhaloalkyl of 1 to 6 carbon atoms, or aryl;
R8 is hydrogen, alkyl of 1 to 6 carbon atoms, perhaloalkyl of 1 to 6 carbon atoms, cycloalkyl of 3 to 10 carbon atoms, heterocycloalkyl of 3 to 10 members, aryl or heteroaryl, or
R7 and R8, taken together may form a 3 to 7 membered heterocycloalkyl;
R9-R12 are independently hydrogen, alkyl of 1 to 4 carbon atoms, perhaloalkyl of 1 to 4 carbon atoms, halogen, alkoxy of 1 to 4 carbon atoms, or cyano, or R9 and R10 or R11 and R12may be taken together to form aryl of 5 to 7 carbon atoms;
W is O, NR6, or is absent;
Y is xe2x80x94(CO)xe2x80x94 or xe2x80x94(CO2)xe2x80x94, or is absent;
Z is alkyl of 1 to 4 carbon atoms, xe2x80x94CN, xe2x80x94CO2R6, COR6, xe2x80x94CONR7R8, xe2x80x94OCOR6, xe2x80x94NR6COR7, xe2x80x94OCONR6, xe2x80x94OR6, xe2x80x94SR6, xe2x80x94SOR6, xe2x80x94SO2R6, SR6N(R7R8), xe2x80x94N(R7R8) or phenyl;
G is alkyl of 1 to 6 carbon atoms; and
X is a bond, xe2x80x94NH, alkyl of 1 to 6 carbon atoms, alkenyl of 1 to 6 carbon atoms, alkoxy of 1 to 6 carbon atoms, thioalkyl of 1 to 6 carbon atoms, alkylamino of 1 to 6 carbon atoms, or (CH)J;
J is alkyl of 1 to 6 carbon atoms, cycloalkyl of 3 to 7 carbon atoms, phenyl or benzyl;
and n is an integer from 1 to 6; or a pharmaceutical salt thereof.
In some preferred embodiments of the present invention at least one of R1-R5 is not hydrogen. In some preferred embodiments at least one of R1-R5 is a halogen. In more preferred embodiments R2 and/or R4 are chlorine.
In some preferred embodiments of the present invention each of R9-R12 is hydrogen. In other embodiments of the present invention, at least 1 of R9-R12 is not hydrogen. Preferably R9-R12 are selected from halogen. methyl, methoxy, and cyano.
G is preferably methyl.
Preferred compounds of the present invention are the following compounds which include pharmaceutical salts thereof. N-{4-[3-(3,5-Dichloro-4-methoxy-phenyl)-thioureido]-phenyl}-acetamide;
N-{4-[3-(3,5-Dichloro-4-ethoxy-phenyl)-thioureido]-phenyl}-acetamide;
N-{4-[3-(3,5-Dichloro-2-methoxy-4-methyl-phenyl)-thioureido]-phenyl}-acetamide;
N-{4-[3-(5-Chloro-2-methoxy-4-methyl-phenyl)-thioureido]-phenyl}-acetamide;
N-(4-{3-[3-Chloro-4-(cyclohexyl-methyl-amino)-phenyl]-thioureido}-phenyl)-acetamide;
N-(4-{3-[4-(1-Benzyl-pyrrolidin-3-yl)amino)-3-chloro-phenyl]-thioureido}-phenyl)-acetamide:
N-{4-[3-(3-Chloro-4-vinyl-phenyl)-thioureido]-phenyl}-acetamide;
N-{4-[3-(3-Chloro-4-methylsulfanyl-phenyl)-thioureido]-phenyl}-acetamide;
N-[4-(3-{4-[(1-Benzyl-pyrrolidin-3-yl)-methyl-amino]-3-chloro-phenyl}-thioureido)-phenyl]-acetamide;
N-[4-(3-{3-Chloro-4-[methyl-(1-methyl-piperidin-4-yl)-amino]-phenyl}-thioureido)-phenyl]-acetamide;
N-[4-(3-{3-Chloro-4-[methyl-(1-methyl-piperidin-4-yl)-amino]-phenyl}-thioureido)-phenyl]-acetamide;
N-{4-[3-(3-Chloro-4-iodo-phenyl)-thioureido]-phenyl}-acetamide;
N-{4-[3-(3-Chloro-4-trifluoromethyl-phenyl)-thioureido]-phenyl}-acetamide; and
N-{4-[3-(3-Chloro-4-isoxazol-5-yl-phenyl)-thioureido]-phenyl}-acetamide.
Alkyl as used herein refers to straight or branched chain lower alkyl of 1 to 6 carbon atoms. Exemplary alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl and hexyl.
Alkenyl as used herein refers to straight or branched chain lower alkyl ot 2 to 6 carbon atoms containing at least one carbon-carbon double bond. Alkenyl includes vinyl groups.
Alkynyl as used herein refers to straight or branched chain lower alkyl of 2 to 6 carbon atoms containing at least one carbon-carbon triple bond.
Alkyl, alkenyl and alkynyl groups of the present invention may be substituted or unsubstituted.
Cycloalkyl refers to a saturated mono or bicyclic ring system of 3 to 10 carbon atoms. Exemplary cycloalkyl groups include cyclopentyl, cyclohexyl and cycloheptyl. Cycloalkyl groups of the present invention may be substituted or unsubstituted.
Heterocycloalkyl refers to a saturated mono or bicyclic ring system of 3 to 10 members having 1 to 3 heteroatoms selected from N, S and O, including, but not limited to aziridinyl, azetidinyl, imidazolidinyl, morpholinyl, thiomorpholinyl, piperazinyl, pyrazolidinyl, piperidinyl, and pyrrolidinyl. Heterocycloalkyl groups of the present invention may be substituted or unsubstituted.
Aryl, as used herein refers to an aromatic mono or bicyclic ring of 5 to 10 carbon atoms. Exemplary aryl groups include phenyl, naphthyl, and biphenyl. Aryl groups of the present invention may be substituted or unsubstituted.
Heteroaryl as used herein refers to an aromatic mono or bicyclic ring of 5 to 10 members having 1 to 3 heteroatoms selected from N, S or O including, but not limited to thiazolyl, thiadiazolyl, oxazolyl, furyl, indolyl, benzothiazolyl, benzotriazolyl, benzodioxyl, indazolyl, and benzofuryl. Preferred heteroaryls include quinolyl, isoquinolyl, napthalenyl, benzofuranyl, benzothienyl, indolyl, pyridyl, pyrazinyl, thienyl, furyl, pyrrolyl, isoxazolyl, oxazolyl, isothiazolyl, thiazolyl, pyrazolyl, triazolyl, thiadiazolyl, and imidazolyl. Heteroaryl groups of the present invention may be substituted or unsubstituted.
Perhaloalkyl refers to an alkyl group of 1 to 6 carbon atoms in which three or more hydrogens are substituted with halogen.
Phenyl as used herein refers to a 6 membered aromatic ring.
Halogen, as used herein refers to chlorine, bromine, iodine and fluorine.
Unless otherwise limited substitutents are unsubstituted and may include alkyl of 1 to 6 carbon atoms, cycloalkyl of 1 to 6 carbon atoms, heterocycloalkyl of 1 to 6 members, perhaloalkyl of 1 to 6 carbon atoms, alkylamino, dialkylamino, aryl or heteroaryl.
Carbon number refers to the number of carbons in the carbon backbone and does not include carbon-atoms occurring in substituents such as an alkyl or alkoxy substituents.
Where terms are used in combination, the definition for each individual part of the combination applies unless defined otherwise. For instance, alkylcycloalkyl is an alkyl-cycloalkyl group in which alkyl and cycloalkyl are as previously described.
Pharmaceutically acceptable salts are the acid addition salts which can be formed from a compound of the above general formula and a pharmaceutically acceptable acid such as phosphoric, sulfuric, hydrochloric, hydrobromic, citric, maleic, succinic, fumaric, acetic. lactic, nitric, sulfonic, p-toluene sulfonic, methane sulfonic acid, and the like.
The compounds of this invention contain a chiral center, providing for various seteroisomeric forms of the compounds such as racemic mixtures as well as the individual optical isomers. In some preferred embodiments of the present invention the compounds of the present invention are substantially pure optical isomers. By substantially pure is meant the composition contains greater than 75% of the desired isomer and may include no more than 25% of the undesired isomer. In more preferred embodiments the pure optical isomer is greater than 90% of the desired isomer. In some preferred embodiments, when the target is VZV, the (S) isomer is preferred. The individual isomers can be prepared directly or by asymmetric or stereospecific synthesis or by conventional separation of optical isomers from the racemic mixture.
Compounds of the present invention may be prepared by those skilled in the art of organic synthesis employing methods described below which utilize readily available reagents and starting materials unless otherwise described. Compounds of the present invention are thus prepared in accordance with the following schemes.
The novel compounds of the present invention are prepared according to the following reaction schemes.
Referring to Methods 31 and 34, reacting appropriately substituted amines 2, wherein the substitutents R1-R5, and X are described as above, with appropriately substituted isothiocyanates 3, wherein the substituents R9-R12 and G are described above, either neat or in an appropriate solvent such as tetrahydrofuran, acetonitrile, ethyl acetate, dichloromethane, or N,N-dimethylformamide affords the desired thioureas 1. Similarly, reaction of appropriately substituted isothiocyanates 4, wherein the substitutents R1-R5, and X are described as above with appropriately substituted anilines 5, wherein the substituents R9-R12 and G are described above, in a convenient solvent such as those listed above affords the desired thioureas 1. 
Alternatively, appropriately substituted thioureas 1 can be prepared as described by Methods 32 and 33 by reacting amines 2 and 5, wherein R1-R5, R9-R12 and G arc described as above, in the presence of either one molar equivalent of 1,1xe2x80x2-thiocarbonyl diimidazole in an appropriate solvent such as dichloro-methane and tetrahydrofuran or mixtures thereof or one molar equivalent of 1,1xe2x80x2-thiocarbonyl-di-(1,2,4)-triazole in an appropriate solvent such as dichloromethane and tetrahydrofuran or mixtures thereof at room temperature. 
In certain instances, sequent chemical modification of the final thioureas 1 was required. Methods 35-39, are summarized below. 
Thioureas 1 wherein at least one substituent of R1-R5 is 1-hydroxyethoxy or carboxy-methoxy, R9-R12 and G are defined as above and X equals a bond, may be prepared from the corresponding alkyl esters by alkaline hydrolysis with aqueous sodium or potassium hydroxide in a suitable solvent such as methanol, tetrahydrofuran or mixtures thereof at room temperature in accordance with Methods 35 and 36.
Thioureas 1 wherein at least one substituent of R1-R5 is 1-acyloxyethoxy or methansulfonoxyethoxy, R9-R12 and G are defined as above and X equals a bond, may be prepared from the corresponding 1-hydroxyethoxy derivative by acylation with appropriate acylating agents such as benzoic acid chloride or methanesulfonic acid chloride in the presence of a suitable tertiary amine base such as triethylamine or diisopropylethylamine in a suitable solvent such as dichloromethane or the like at room temperature in accordance with Methods 37 and 38.
Thioureas 1 wherein at least one substituent of R1-R5 is 1-aminoethoxy, R9-R12 and G are defined as above and X equals a bond, may be prepared from the corresponding 1-methanesulfonoxy-ethoxy derivative by reaction with an appropriate secondary amine such as dimethylamine in a suitable solvent mixture such as tetrahydrofuran and water or the like at room temperature in accordance with Method 39.
Thioureas 1 wherein at least one substituent of R1-R5 is 1-aminoalkyl, R9-R12 and G are defined as above and X equals a bond, may be prepared from the corresponding 1-azidoalkyl derivative by reaction with stannous chloride in a suitable solvent such as methanol, ethanol or the like at room temperature in accordance with Method 40.
The intermediate isothiocyanates 3 and 4 shown above in Methods 31 and 34 are prepared in accordance with Method 41 (below) essentially according to the procedures of Staab, H. A. and Walther, G. Justus Liebigs Ann. Chem. 657, 104 (1962)) by reacting appropriately substituted amines 5 or 2, respectively, wherein R1-R5, R9-R12 and G are described above and X is defined above, with one molar equivalent of 1,1xe2x80x2-thiocarbonyldiimidazole in an appropriate solvent such as dichloromethane and tetrahydrofuran or mixtures thereof. 
The intermediates 2 and 5 may be prepared according to the following protocols:
According to Methods 1A-1G, amines 2, wherein R1-R5 are defined above and X is defined above and amines 5, wherein R9-R12 are defined above, may be prepared by reduction of the appropriately substituted nitrobenzenes according to a variety of procedures known to those skilled in the art and described in R. J. Lindsay, Comprehensive Organic Chemistry (ed. Sutherland), Volume 2, Chapter 6.3.1, Aromatic Amines, 1979. Such procedures include the reduction of nitrobenzenes to form anilines upon exposure to:
a) iron powder and a strong acid, such as hydrochloric acid (Methods 1A) either neat or in alcohol solvent such as methanol or ethanol, at temperatures ranging from room temperature to the refluxing temperature of the solvent, or;
b) iron powder and glacial acetic acid (Method 1B), either neat or in alcohol solvent such as methanol or ethanol, at temperatures ranging from room temperature to the refluxing temperature of the solvent, or;
c) iron powder and aqueous ammonium chloride (Method 1C), either neat or in alcohol solvent such as methanol or ethanol, at temperatures ranging from room temperature to the refluxing temperature of the solvent, or;
d) tin and a strong mineral acid, such as hydrochloric acid (Method 1D), either neat or in alcohol solvent such as methanol or ethanol, at temperatures ranging from room temperature to the refluxing temperature of the solvent, or;
e) when R1-R5 and R9-R are selected from Cl, Br, I, xe2x80x94(OSO2)xe2x80x94CF3, or xe2x80x94(OSO2)-1-(4-methylphenyl), by catalytic reduction such as with hydrogen and palladium on carbon (Method 1E) in an appropriate solvent such as methanol, ethanol, or ethyl acetate, under one or more atmospheres of pressure or;
f) when R1-R5 and R9-R12 are selected from Cl, Br, I, xe2x80x94(OSO2)xe2x80x94CF3, or xe2x80x94(OSO2)-1-(4-methylphenyl), by catalytic reduction such as with cyclohexene and palladium on carbon (Method 1F) in an appropriate solvent such as methanol or ethanol, at temperatures ranging from room temperature to the refluxing temperature of the solvent, or:
g) aqueous sodium hydrosulfite in alcohol solvent at temperatures ranging from room temperature to the refluxing temperature of the solvent (Method 1G).
Alternatively, according to Methods 3A-3C, amines 2, wherein R1-R5 are defined above and X is defined above and anilines 5, wherein R9-R12 are defined above, may be prepared by the cleavage of the aniline nitrogen-carbon bond of amide and carbamate derivatives of these anilines according to a variety of procedures known to those skilled in the art and described in Greene, Protective Groups in Organic Synthesis volume 2, Chapter 7, 1991, and references therein. Such procedures include:
a) the exposure of appropriately substituted arylamino-tert-butyl-carbamates to a strong acid such as trifluoroacetic acid (Method 3A) either neat or in an appropriate solvent such as dichloromethane at temperatures between 0xc2x0 C. and room temperature, or;
b) the exposure of appropriately substituted arylamino-(2-trimethylsilylethyl)-carbamates to a fluoride ion source such as tetrabutylammonium fluoride or potassium fluoride (Method 3B) in aqueous acetonitrile or tetrahydrofuran or mixtures thereof at temperatures ranging from room temperature to the reflux temperature of the solvent, or;
c) the exposure of appropriately substituted arylamino-trifluoroacetamides to a strong base such as sodium or potassium hydroxide or sodium or potassium carbonate in an alcohol solvent such as methanol or ethanol (Method 3C) at temperatures ranging from room temperature to the reflux temperature of the solvent.
Alternatively, according to Method 11, amines 2, wherein R1-R5 are defined above, and X equals a bond and at least one substituent of R1-R5 is defined as vinyl, may be prepared by the palladium catalyzed coupling of a vinyl trialkyltin reagent, such as tributylvinyltin, with an appropriately substituted bromo- or iodo-aniline, for example 3-chloro-4-iodo-aniline, employing a palladium catalyst, such as tris(dibenzylidineacetone)-bipalladium, and a ligand, such as triphenylarsine, in a suitable solvent such as tetrahydrofuran or N-methylpyrrolidinone, at temperatures ranging from room temperature to the reflux temperature of the solvent, essentially according to the procedures of V. Farina and G. P. Roth in Advances in Metal-Organic Chemistry, Vol. 5, 1-53, 1996 and references therein.
Alternatively, according to Method 42, amines 2, wherein R1-R5 are defined above and X is defined above and at least one substituent of R2 or R4 is defined as dialkylamino, may be prepared by the palladium catalyzed amination of an appropriately substituted 3- or 5-bromo- or iodo-aniline, for example 3-amino-5-bromobenzo-trifluoride, by secondary amines under conditions which employ a palladium catalyst, such as bis(dibenzylidineacetone)palladium, and a ligand, such as tri-o-tolylphosphine, and at least two molar equivalents of a strong base, such as lithium bis-(trimethylsilyl)amide in a sealed tube, in a suitable solvent such as tetrahydrofuran or toluene, at temperatures ranging, from room temperature to 100xc2x0 C., essentially according to the procedures of J. F. Hartwig and J. Louie Tetrahedron Letters 36 (21), 3609 (1995).
Alternatively, according to Method 43, amines 2, wherein R1-R5 are defined above and X is defined above and at least one substituent of R2 or R4 is defined as alkyl, may be prepared by the palladium catalyzed alkylation of an appropriately substituted 3- or 5-bromo-or iodo-aniline, for example 3-amino-5-bromobenzotrifluoride by alkenes under conditions which employ a palladium catalyst such as [1,1xe2x80x2-bis(diphenylphosphino)ferrocene]palladium(II) chloride-dichloromethane complex and in the presence of 9-borabicyclo[3.3.1]nonane and a suitable base such as aqueous sodium hydroxide in a suitable solvent such as tetrahydrofuran or the like at temperatures ranging from room temperature to the reflux temperature of the solvent.
The acyl and carbamoyl amine derivatives utilized as starting materials in Methods 3A-3C may be prepared by the derivatization of the corresponding amines as described in Methods 2A-2G according to a variety of procedures known to those skilled in the art and described in Greene, Protective Groups in Organic Synthesis volume 2, Chapter 7, 1991, and references therein. Such procedures include:
a) the reaction of an appropriately substituted amine with di-tert-butyl-dicarbonate (Method 2A) in the presence or absence of one or more molar equivalents of a tertiary amine such as triethylamine or N,N-diisopropylethylamine in a suitable solvent such as acetone, tetrahydrofuran, dimethylformamide, dichloromethane, and the like, at temperatures ranging from room temperature to the reflux temperature of the solvent to produce the corresponding arylamino-tert-butyl-carbamate, or:
b) the reaction of an appropriately substituted aniline with 1-[2-(trimethylsilyl)ethoxycarbonyl-oxy]benzotriazole (Method 2B) in the presence of a tertiary amine such as triethylamine or diisopropylethylamine in a suitable solvent such as dimethylformamide at room temperature to produce the corresponding arylamino-(2-trimethylsilylethyl)-carbamate, or;
c) the reaction of an appropriately substituted aniline with a carboxylic acid chloride or acid anhydride (Method 2C) either neat or in an appropriate solvent such as tetrahydrofuran, dimethylformamide, dichloromethane, pyridine and the like, in the presence of one or more molar equivalents of a teriary amine base such as triethylamine or N,N-diisopropylethyl-amine to produce the corresponding arylaminoamide, or;
d) the reaction of an appropriately substituted nitro aniline with a carboxylic acid chloride (Method 2D) in the absence of one or more molar equivalents of a teriary amine base such as triethylamine or N,N-diisopropylethylamine either neat or in an appropriate solvent such as tetrahydrofuran, 1,4-dioxane and the like at temperatures ranging from room temperature to the reflux temperature of the solvent to produce the corresponding nitro arylaminoamide, or;
e) the reaction of an appropriately substituted aniline with a carboxylic acid (Method 2E) in the presence of a coupling agent such as benzotriazole-1-yloxy-tris-(dimethylamino)-phosphonium hexafluorophosphate, 2-(1H-benzotriazole-1-yloxy)-1,1,3,3-tetra-methyluronium hexafluorophosphate, dicyclohexyl carbodiimide and the like and in the presence of a tertiary amine such as triethylamine or diisopropylethylamine in a suitable solvent such as diichloromethane, dimethylformamide and the like, at room temperature to produce the corresponding arylaminoamide, or;
f) the reaction of an appropriately protected aniline such as an arylamino-tert-butyl-carbamate or the like in which at least one substituent of R9-R12 is defined as xe2x80x94Wxe2x80x94Yxe2x80x94(CH2)nxe2x80x94Z wherein W, Y, and Z are defined as above, with a carboxylic acid anhydride (Method 2F) in the presence of a suitable base such as pyridine in an appropriate such as dichloromethane, dimethylformamide or the like at temperatures ranging from 0xc2x0 C. to room temperature to produce the corresponding carboxylic acid ester, or;
g) the reaction of an appropriately substituted aniline in which at least one substituent of R1-R5 is defined as hydroxyl with di-tert-butyl-dicarbonate (Method 2G) in the absence of one or more molar equivalents of a tertiary amine such as triethylamine or N,N-diisopropylethylamine in a suitable solvent such as acetone, tetrahydrofuran, dimethylformamide, dichloromethane, and the like, at temperatures ranging from room temperature to the reflux temperature of the solvent to produce the corresponding arylamino-tert-butyl-carbamate.
Nitrobenzene intermediates that are ultimately converted to amines 2 and 5 by methods shown above in Methods 1A-1G may be prepared in accordance with Methods 4A, 4C, 4E-4F.
Referring to Methods 4A, 4C, and 4E-4H, the nitrobenzene intermediates which are ultimately converted into amines 2, R2 and R4 are defined above and R1, R3, and/or R5 are defined as alkoxy, thioalkoxy, alkylsulfenyl, alkylsulfinyl, and dialkylamino may be prepared by the nucleophilic displacement of appropriately substituted 2-, 4-, and/or 6-fluoro-, chloro-, bromo-, iodo-, trifluoromethylsulfonyl-, or (4-methylphenyl)sulfonyl-substituted nitrobenzenes by methods which include the following:
a) reaction of alcohols with appropriately substituted 2- or 4- halo- or sulfonate esters of nitrobenzenes or benzonitriles (Method 4A) either neat or in an appropriate solvent such as tetrahydrofuran, dioxane, acetonitrile, N,N-dimethylformamide or dimethylsulfoxide in the presence or absence of one or more molar equivalents of a base such as sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium hydride, potassium hydride, or the like, at temperatures ranging from room temperature to the reflux temperature of the solvent;
b) reactions of preformed sodium, lithium, or potassium phenoxides with appropriately substituted 2- or 4-halo- or sulfonate esters of nitrobenzenes or benzonitriles (Method 4H) either neat or in an appropriate solvent such as tetrahydrofuran, dioxane, acetonitrile, N,N-dimethylformamide or dimethylsulfoxide, at temperatures ranging from room temperature to the reflux temperature of the solvent, or;
c) reaction of ammonia, primary or secondary amines with appropriately substituted 2- or 4-halo- or sulfonate esters of nitrobenzenes or benzonitriles (Methods 4C,F) either neat or in an appropriate solvent such as tetrahydrofuran, dioxane, acetonitrile, N,N-dimethyl-formamide or dimethylsulfoxide, at temperatures ranging from room temperature to the reflux temperature of the solvent;
d) reaction of preformed sodium, lithium, or potassium salts of amines with appropriately substituted 2- or 4- halo- or sulfonate esters of nitrobenzenes or benzonitriles (Method 4G) in an appropriate solvent such as tetrahydrofuran at temperatures ranging from 0xc2x0 C. to the reflux temperature of the solvent, or;
e) reaction of sodium sulfide with appropriately substituted 2- or 4- halo- or sulfonate esters of nitrobenzenes or benzonitriles either neat or in an appropriate solvent such as tetrahydro-furan, dioxane, acetonitrile, N,N-dimethylformamide or dimethylsulfoxide, at temperatures ranging from room temperature to the reflux temperature of the solvent, followed by the addition of an alkyl halide directly to the reaction mixture (Method 4E).
Alternatively, referring to Methods 5C and 6, the nitrobenzene intermediates which are ultimately converted into amines 2, wherein at least one substitutent R1-R5 is defined as alkoxy may be prepared from the corresponding substituted hydroxy-nitrobenzenes by methods which include the following:
a) reaction of the hydroxy-nitrobenzene with an alkyl halide or dialkyl sulfonate ester (Method 5C) in the presence of a base, such as potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, potassium hydride, or sodium hydride, in an appropriate solvent such as acetone, N,N-dimethylformamide, tetrahydrofuran or dimethylsulfoxide at temperatures ranging from room temperature to the reflux temperature of the solvent, or
b) reaction of the hydroxy-nitrobenzene with an alkyl alcohol, triphenylphosphine, and a dialkylazadicarboxylate reagent (Method 6), such as diethylazodicarboxylate, in an anhydrous aprotic solvent such as diethyl ether or tetrahydrofuran at temperatures ranging from 0xc2x0 C. to the reflux temperature of the solvent, essentially according to methods described in Mitsunobu, O, Synthesis 1981, 1 and references therein.
In addition, referring to Method 5A and 5E, the carbamoyl amine derivatives utilized as starting materials in Methods 3A-3C which are ultimately converted into amines 2, wherein at least one substituent R1-R5 is defined as alkoxy may be prepared the corresponding substituted hydroxy arylamino-tert-butyl-carbamate by reaction with alkyl halides, trifluormethane-sulfonates, 4-methylbenzenesulfonates, dialkylsulfonate, ethylene carbonate and the like in the presence of a suitable base such as potassium carbonate in an appropriate solvent such as acetone, toluene, or N,N-dimethyl-formamide at temperatures ranging from room temperature to the reflux temperature of the solvent.
Alternatively, referring to Methods 7A-G, the nitrobenzene intermediates which are ultimately converted into amines 2, R1 and/or R3 is alkoxy, and R2 and/or R4 is a halogen, and X equals a bond, may be prepared by standard halogenation reactions which include the following:
a) reaction of a 2- or 4-hydroxy-nitrobenzene with aqueous sodium hypochlorite (Methods 7A and 7B), at room temperature or;
b) reaction of a 2-hydroxy-4-methoxy or 2,4-dimethoxynitrobenzene (Method 7C and 7D) with bromine in suitable solvent such as chloroform, dichlormethane, glacial acetic acid or the like in the presence or the absence of silver trifluoroacetate at room temperature, or;
c) reaction of a 2,4-dimethoxynitrobenzene (Method 7E) with benzyltrimethyl-ammonium dichloroiodate in the presence of anhydrous zinc chloride in a suitable solvent such as glacial acetic acid, at room temperature or:
d) reaction of a 2-hydroxy-4-methoxynitrobenzene (Method 7F) with benzyltrimethyl-ammonium dichloroiodate in the presence of sodium bicarbonate in a suitable solvent mixture such as dichloromethane and methanol, at room temperature or;
e) reaction of a 2,4-dimethoxynitrobenzene (Method 7G) with 3,5-dichloro-1-fluoropyridine triliate in a suitable solvent such as tetrachloroethane, at a to temperature ranging from room temperature to the reflux temperature of the solvent.
Referring to Method 8, the nitrobenzene intermediates which are ultimately converted into amines 2, wherein R4=xe2x80x94CF3, and R1-R3 and R5-R8 are defined as above and X equals a bond may be prepared from the corresponding substituted 4-iodo-nitrobenzenes by reaction with trimethyl(trifluoromethyl)silane in the presence of cuprous iodide and potassium fluoride in a suitable solvent such as N,N-dimethyl-formamide or the like at a temperature ranging from room temperature to the reflux temperature of the solvent in a sealed reaction vessel.
Referring to Methods 19A and 19B, the nitrobenzene intermediates which are ultimately converted into amines 2, wherein R4=xe2x80x94HNCOCH2NR7R8 or xe2x80x94HNCOCH2SR6, and R1-R3 and R5-R8 are defined as above and X equals a bond may be prepared from the corresponding substituted 4-(N-chloroacetyl)-nitroaniline by reaction with either a suitable secondary amine such as dimethylamine, morpholine or the like in a suitable solvent such as tetrahydrofuran and/or water mixtures at temperatures ranging from room temperature to the reflux temperature of the solvent or by reaction with an appropriate thiol in the presence of a suitable base such as sodium or potassium carbonate or the like in a suitable solvent such as tetrahydrofuran, 1,4-dioxane or the like at temperatures ranging from room temperature to the reflux temperature of the solvent.
Referring to Method 25, the nitrobenzene intermediates which are ultimately converted into amines 2, wherein at least one substituent of R1-R5 is defined as triflate and X equals a bond may be prepared from the corresponding phenol by reaction with trifluoromethane sulfonic anhydride in the presence of a tertiary amines such as triethylamine or diisopropyl-ethylamine or the like in a suitable solvent such as dichloromethane at temperatures ranging from 0xc2x0 C. to room temperature.
Referring to Methods 9, 9B, and 10, the carbamoyl amine derivatives utilized as starting materials in Methods 3A-3C which are ultimately converted into amines 2, wherein at least one substituent R1-R5 is defined as either alkylsulfenyl or alkylsulfinyl, may be prepared by reaction of the appropriate 4-alkylthio acylarylamino or carbamoyl arylamino derivative with an appropriate oxidizing agent such as dimethyloxirane or sodium periodate in a suitable solvent mixture such as acetone and dichloromethane or water at room temperature.
Referring to Method 12, the carbamoyl amine derivatives utilized as starting materials in Methods 3A-3C which are ultimately converted into amines 2, wherein R4 is defined as 1-hydroxyethyl and R1-R3 and R5 are defined as above and X equals a bond may be prepared by reacting the corresponding 4-vinyl carbamoyl aniline with sodium borohydride in the presence of mercuric acetate in a suitable solvent such as tetrahydrofuran, 1,4-dioxane or the like and water at room temperature.
Referring to Method 13, the carbamoyl amine derivatives utilized as starting materials in Methods 3A-3C which are ultimately converted into amines 2, wherein R4 is defined as 2-hydroxyethyl and R1-R3 and R5 are defined as above and X equals a bond, may be prepared by reacting the corresponding 4-vinyl carbamoyl aniline with sodium borohydride in the presence of glacial acetic acid in a suitable solvent such as tetrahydrofuran, 1,4-dioxane or the like at temperatures ranging from 0xc2x0 C. to room temperature.
Referring to Method 14, the carbamoyl amine derivatives utilized as starting materials in Methods 3A-3C which are ultimately converted into amines 2, wherein R4 is defined as 1-azidoethyl and R1-R3 and R5 are defined as above and X is defined above may be prepared by reacting the corresponding 4-(1-hydroxyethyl) carbamoyl aniline with hydrazoic acid in the presence of a dialkylazodicarboxylate such as diethylazodicarboxylate and triphenylphosphine in a suitable solvent mixture such as tetrahydrofuran and dichloromethane at temperatures ranging from 0xc2x0 C. to room temperature.
Referring to Method 15, the carbamoyl amine derivatives utilized as starting materials in Methods 3A-3C which are ultimately converted into amines 2, wherein R4 is defined as 3-dimethylaminoprop-1-ynyl and R1-R3 and R5 are defined as above and X is defined above, may be prepared by reacting the corresponding 4-iodocarbamoyl aniline with 1-dimethylamino-2-propyne in a suitable tertiary amine solvent such as triethylamine or diisopropylethylamine in the presence of bis(triphenylphosphine)palladium(II) chloride and cuprous iodide at temperatures ranging from room temperature to the reflux temperature of the solvent.
Referring to Method 16, the carbamoyl amine derivatives utilized as starting materials in Methods 3A-3C which are ultimately converted into amines 2, wherein R4 is defined as 3-dimethylaminoacryloyl and R1-R3 and R5 are defined as above and X equals a bond, may be prepared by reacting the corresponding 4-(3-dimethylaminoprop-1-ynyl)carbamoyl aniline with a suitable peracid such as 3-chloroperoxybenzoic acid in a suitable solvent mixture such as dichloromethane and methanol at temperatures ranging from 0xc2x0 C. to room temperature.
Referring to Methods 17 and 18, the carbamoyl amine derivatives utilized as starting materials in Methods 3A-3C which are ultimately converted into amines 2, wherein R4 is defined as either 4-isoxazol-5-yl or 4-(1H-pyrazol-3-yl) and R1-R3 and R5 are defined as above and X equals a bond, may be prepared by reacting the corresponding 4-(3-dimethylamino-acryloyl)carbamoyl aniline with either hydroxylamine hydrochloride or hydrazine hydrate in a suitable solvent such as 1,4-dioxane or ethanol and the like at room temperature.
Referring to Method 20, the carbamoyl amine derivatives utilized as starting materials in Methods 3A-3C which are ultimately converted into amines 2, wherein R4=xe2x80x94HNCO2Z, and R1-R3, R5, and Z are defined as above and X equals a bond, may be prepared by reacting the corresponding 4-aminocarbamoyl aniline with 1,1-carbonyl-di-(1,2,4)-triazole and an appropriately substituted alcohol in a suitable solvent mixture such as tetrahydrofuran and dichloromethane and the like at temperatures ranging from room temperature to the reflux temperature of the solvent.
Referring to Methods 26 and 30, the carbamoyl amine derivatives utilized as starting materials in Methods 3A-3C which are ultimately converted into amines 2, wherein at least one substituent of R1-R5 is defined as dialkylamino and X is defined above may be prepared by reaction of appropriately substituted aldehydes in the presence of either sodium cyanoboro-hydride or hydrogen gas and 10% palladium on carbon in a suitable solvent such as water, methanol, tetrahydrofuran mixtures or toluene or the like at room temperature.
Referring to Methods 27 and 28, amines 2 wherein at least one substituent of R1-R5 is defined as hydroxy and X is defined above can be prepared by reaction of the corresponding ester such as acetate with an appropriate base such as sodium bicarbonate or sodium hydroxide in a suitable solvent mixture such as methanol-water mixtures at temperatures ranging from room temperature to the reflux temperature of the solvent.
Referring to Method 29, amines 2 wherein at least one substituent of R1-R5 is defined as 2-hydroxybenzamido and X is defined above can be prepared by reaction of the corresponding N-(4-aminophenyl)phthalimide with lithium borohydride in an appropriate solvent such as tetrahydrofuran, diethyl ether, or the like at room temperature.
The intermediate amines 2 wherein R1-R5 are defined as above and X equals either xe2x80x94CH2xe2x80x94 or xe2x80x94(CH2)2xe2x80x94 can be prepared by the following procedures:
a) reduction of an appropriately substituted benzo- or phenylacetonitrile with borane-dimethylsulfide complex in a suitable solvent such as ethylene glycol dimethyl ether, tetrahydrofuran or the like a temperatures ranging from room temperature to the reflux temperature of the solvent. (Method 44);
11. reduction under one or more atmospheres of hydrogen in the presence of a suitable catalyst such as 5% or 10% palladium on carbon and an acid such as 4-methyl-benzenesulfonic acid, hydrochloric acid or the like in a suitable solvent such as ethylene glycol monomethyl ether, ethyl acetate, ethanol or the like at room temperature. (Method 50);
12. reduction with lithium aluminum hydride in a suitable solvent such as tetrahydrofuran or diethyl ether at temperatures ranging from 0xc2x0 C. to room temperature. (Method 51);
The unsaturated nitro precursors which are utilized as starting materials in Method 51 and are ultimately converted to amines 2 wherein R1-R5 are defined as above and X equals xe2x80x94(CH2)2xe2x80x94 can be prepared by reaction of an appropriately substituted benzaldehyde with nitro-methane in the presence of ammonium acetate in a suitable solvent such as acetic acid at temperatures ranging from room temperature to the reflux temperature of the solvent.(Method 53); The benzaldehydes, utilized as starting materials in Method 53, can be prepared by diisobutylaluminum hydride reduction of an appropriately substituted benzonitrile. (Method 52) The substituted benzonitriles, utilized as starting materials in Method 52, can be prepared from the corresponding aryl bromide by reaction with copper cyanide in a suitable solvent such as N,N-dimethylformamide at temperatures ranging from room temperature to the reflux temperature of the solvent. (Method 59)
For amines 2, wherein R1-R5 is defined as above and X equals either xe2x80x94O(CH2)2NH, or xe2x80x94S(CH2)2NH2, the requisite nitrile precursors may be prepared by reaction of an appropriately substituted phenol or thiophenol with bromoacetonitrile in the presence of a suitable base such as potassium carbonate in an appropriate solvent such as acetone at room temperature according to Method 49.
Alternatively, for amines 2, wherein R1-R5 are defined as above and X equals xe2x80x94(CH2)3xe2x80x94, the nitrile precursors can be prepared essentially according to the procedure of Wilk, B. Synthetic Comm. 23, 2481 (1993), by reaction of an appropriately substituted phenethanol with acetone cyanohydrin and triphenylphosphine in the presence of a suitable azodicarboxylate such as diethyl azodicarboxylate in an appropriate solvent such as diethyl ether or tetrahydro-furan or the like at temperatures ranging from 0xc2x0 C. to room temperature. (Method 54)
Alternatively, intermediate amines 2 wherein R1-R5 are defined as above and X equals xe2x80x94(CH(CH3))xe2x80x94 can be prepared by acid or base catalyzed hydrolysis of the corresponding formamide using an appropriate acid catalyst such as 6N hydrochloric acid or a suitable base catalyst such as 5N sodium or potassium hydroxide in an appropriate solvent mixture such as water and methanol or water and ethanol at temperatures ranging from room temperature to the reflux temperature of the solvent. (Method 46)
The formamide precursors utilized as starting materials in Method 46 and which are ultimately converted into amines 2, are prepared according to Method 45 by treatment of an appropriately substituted acetophenone with ammonium formate, formic acid and formamide at temperatures ranging from room temperature to the reflux temperature of the solvent.
Alternatively, amines 2 wherein R1-R5 are defined as above and X equals xe2x80x94(CH(CH3))xe2x80x94 can be prepared by reduction of an appropriately substituted O-methyl oxime in the presence of sodium borohydride and zirconium tetrachloride in a suitable solvent such as tetrahydrofuran or diethyl ether at room temperature Method 48 essentially according to the procedure of Itsuno, S., Sakurai, Y., Ito, K. Synthesis 1988, 995. The requisite O-methyl oximes can be prepared from the corresponding acetophenone by reaction with methoxylamine hydrochloride and pyridine in a suitable solvent such as ethanol or methanol at temperatures ranging from room temperature to the reflux temperature of the solvent. (Method 47) Amines 2 for which R1-R5 are defined as above and X equals xe2x80x94CH(J)xe2x80x94 where J is defined as above, can be prepared by reduction of the appropriately substituted ketone by the methods described above (Methods 45, 47, and 48). These requisite ketones, when not commercially available, can be prepared by reaction of a suitably substituted benzaldehyde with an appropriate organometallic reagent such as phenyllithium, isopropylmagnesium bromide or ethylmagnesium bromide or the like in a suitable solvent such as diethyl ether or tetrahydrofuran at temperatures ranging from xe2x88x9278xc2x0 C. to 0xc2x0 C. (Method 57) The resulting alcohols can be oxidized to the corresponding ketone with an appropriate oxidizing agent such as chromium trioxide in aqueous sulfuric acid and acetone or pyridinium chlorochromate or pyridium dichromate in an appropriate solvent such as dichloromethane or the like at room temperature. (Method 58)
The intermediate anilines 5 may be prepared as previously described Method 3A. Thus treating phenyl carbamic acid tert-butyl ester 6. wherein X equals a bond and G are described as above, with neat trifluoroacetic acid at room temperature followed by neutralization with aqueous sodium hydroxide affords the desired anilines 5. The requisite carbamic acid esters 6, wherein R9-R12 and G are described as above, are prepared as shown in Method 2C by reaction of substituted acid chlorides, 8, where G is described as above, and 4-aminophenylcarbamic acid tert-butyl esters 7, wherein R9-R12 are described above, in the presence of triethylamine in an appropriate solvent such as dichloromethane, dimethylsulfoxide, or dimethylformamide or mixturestthereof. Carboxylic acid chlorides 8 are either commercially available or prepared from the corresponding carboxylic acid by reaction with oxalyl chloride in a suitable solvent such as dichloromethane at room temperature. 
Alternatively, carbamic acid esters 6, wherein R9-R12 and G are described as above, are prepared as shown in Method 2E by reaction of substituted carboxylic acids 8a, wherein G is described as above, and an appropriately substituted 4-aminophenyl carbamic acid tert-butyl esters 7 in the presence of a suitable coupling agent such as benzotriazole-1-yloxy-tris-(dimethylamino)phosphonium hexafluorophosphate, 2-(1H-benzotriazole-1-yloxy)-1,1,3,3-tetramethyluronium hexafluorophosphate, dicyclo-hexyl carbodiimide or the like and in the presence of a tertiary amine base such as triethylamine or diisopropylethylamine in a suitable solvent such as dichloromethane, dimethylformamide and the like, at room temperature to produce the corresponding arylaminoamide.
Carboxylic acids 8a are either commercially available or are prepared according to literature methods. For example, when G is a substituted thiadiazole, the acid is available from the corresponding carboxylic acid ester by reaction with an appropriate base such as sodium or potassium hydroxide in a suitable solvent mixture such as methanol or ethanol and water at room temperature.
Similarly, when G is either substituted or unsubstituted thiazole, substituted or unsubstituted oxazole, substituted or unsubstituted isothiazole or substituted or unsubstituted isoxazole, when not commercially available, the corresponding carboxylic acid 8a is available from the corresponding ethyl or methyl ester by reaction with an appropriate base such as sodium or potassium hydroxide in a suitable solvent mixture such as methanol or ethanol and water at room temperature. These esters are either commercially available or can be prepared according to literature methods.
When the carboxylic acid ester precursors which are ultimately converted to acids 8a are not commercially available, they may be prepared by methods known in the literature. For example, 5-substituted-1,2,3-thiadiazole-4 carboxylic acid esters may be prepared essentially according to the procedure of Caron, M J. Org. Chem. 51, 4075 (1986) and Taber, D. F., Ruckle, R. E. J. Amer. Chem. Soc. 108, 7686 (1986). Thus, according to Method 21, treatment of a beta-keto carboxylic acid ester with 4-methylbenzenesulfonyl azide or methanesulfonyl azide or the like in the presence of a tertiary amine base such triethylamine or diisopropylethylamine in a suitable solvent such as acetonitrile affords the corresponding diazo-beta-keto carboxylic acid ester. Treatment of this compound with 2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide in a suitable solvent such as benzene or toluene or the like at temperatures ranging from room temperature to the reflux temperature of the solvent gives the desired 5-substituted-1,2,3-thiadiazole-4-carboxylic acid ester.
Alternatively, 4-substituted-1,2,3-thiadiazole-5-carboxylic acid esters may be prepared essentially according to the procedure of Shafice, A., Lalezari, I., Yazdani, S., Shahbazian, F. M., Partovi, T. J. Pharmaceutical Sci. 65, 304 (1976). Thus, according to Method 22 and 23, reaction of an appropriately substituted beta-keto carboxylic acid ester in a suitable alcoholic solvent such as methanol or ethanol with an aqueous solution semicarbazide hydrochloride at temperatures ranging from room temperature to the reflux temperature of the solvent in the presence of a suitable base such as pyridine gives corresponding semicarbazone derivative. Treatment of this compound with neat thionyl chloride at 0xc2x0 C. followed by treatment with an excess aqueous solution of sodium bicarbonate affords the corresponding 4-substituted-1,2,3-thiadiazole-5-carboxylic acid esters.
4-carboalkoxythiazoles are prepared essentially according to the procedure of Sch{umlaut over (of)}llkopf, U., Porsch, P., Lau, H. Liebigs Ann. Chem. 1444 (1979). Thus, according to Method 55 and 56, reaction of ethyl isocyanoacetate with N,N-dimethylformamide dimethyl acetal in a suitable alcoholic solvent such as ethanol at room temperature gives the corresponding 3-dimethylamino-2-isocyano-acrylic acid ethyl ester. A solution of this compound in a suitable solvent such as tetrahydrofuran is treated with gaseous hydrogen sulfide in the presence of a suitable tertiary amine base such as triethylamine or diiso-propylethylamine or the like at room temperature to give the corresponding 4-carboethoxy-thiazole.
Additional appropriately substituted thiazoles may be prepared essentially according to the procedure of Bredenkamp, M. W., Holzafel, C. W., van Zyl, W. J. Synthetic Comm. 20, 2235 (1990). Appropriate unsaturated oxazoles are prepared essentially according to the procedure of Henneke, K. H., Sch{umlaut over (of)}llkopf, U., Neudecker, T. Liebigs Ann. Chem. 1979 (1979). Substituted oxazoles may be prepared essentially according to the procedures of Galeotti, N., Montagne, C., Poncet, J., Jouin, P. Tetrahedron Lett. 33, 2807. (1992) and Shin, C., Okumura, K., Ito, A., Nakamura, Y. Chemistry Lett. 1305, (1994).